What does “unfavorable scholastic achievements” mean? Did she get poor grades? If so, I don’t see why other parents should care. However, her parents should have explained to her that she would not succeed in a school that demands scholastic excellence and looked for a less demanding school. What do you want? That she should be given good grades just to make her feel better? I went to public schools in NYC. I was accepted into a “specialized” HS but only received middling grades there. I accepted the fact that while I was not exactly the tail of a lion I was far from the head. For this I thank my father z”l who told me at a very young age that no matter how good you are there is somebody better. Some of my friends were not accepted so they went to a regular HS. That’s the way the ball bounces. Some of them are now doing much better financially than me so it seems that Hashem really does decide how much parnassa each person gets.
On the other hand “unfavorable scholastic achievements” could be a euphemism for disruptiveness (“some of the details were altered”). If she indeed committed suicide over this apparently she was not very stable. This would explain the opposition of the other parents. IMHO if so they were right. They do not have to endanger their children because one girl’s parents miseducate her and will not seek proper help to undo the damage.